Direct positive type silver halide photographic materials for use in applications such as micro COM recorders and lasers for printing have been remarkably developed in recent years. In the field of micro COM, for example, a product for COM recorders employing an He-Ne laser has come into use.
The red-sensitive desensitizing dyes used for such a purpose tend to have impaired reversal sensitivity because the ability of the dye hole to bleach an Ag nucleus is reduced. Hence, a direct positive type silver halide photographic material having good reversal sensitivity to red light has been strongly desired.
A direct positive type silver halide photographic material which is reduced in residual coloring after processing has also been strongly desired.
Although the cyanine dye having a pyrazolo[5,1-b]quinazolone nucleus which dye is used in the present invention is known as described in JP-A-49-29828, all the dye examples given in this reference have a structure in which the methine chain consists of two methine groups and are spectrally sensitized only in the orthochromatic region. (The term "JP-A" as used herein means an "unexamined published Japanese patent application.") The dye used in the present invention has four methine chains and differs from those dyes in that it can be spectrally sensitized in the panchromatic region.
In addition, although dyes similar to the dye represented by formula (I) used in the present invention are described in U.S. Pat. No. 3,431,111 and others, no technique is known which employs a dye combination such as that in the present invention.
Further, since higher processing rates are desirable for photographic materials in such a field, the conveying speed of the photographic materials tends to increase more and more recently. Increased conveying speeds result in increased contact forces between the film (photographic material) and the conveyor rollers. As a result, the film is charged to become apt to attract a foreign substance such as dust particles. If a film to which dust particles are adherent is exposed as it is, this causes problems of pinhole generation and partial sensitization of the film by electrical discharge.
On the other hand, various dyes are often used for the purpose of preventing silver halide photographic materials from suffering halation or irradiation to heighten image sharpness. However, dye selection is difficult because many of these dyes adversely influence the residual colors of processed films.